MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE GUIGANG SALENTO-TYPE BAUXITE DEPOSITS, WESTERN GUANGXI, CHINA

The Guigang bauxite belongs to the rich iron Salento-type bauxite with low alumina silica ratio. Mineralogical investigations show that gibbsite (Al(OH)(3)), diaspore (AlO(OH)), goethite (FeO(OH)) and hematite (Fe2O3) are the major mineral components in the bauxite ores, anatase (TiO2), quartz (SiO2) and Calcite (CaCO3) are minor accessories. Geochemical investigations reveal that the Al2O3 (24.31-26.46 %), Fe2O3 (38.33-44.03 %), SiO2 (8.76-12.27 %) are the major geochemical compositions in the bauxite ores. SEM+EDS analysis shows that most of the diaspores are cryptocrystalline with a small particle size and mainly coexists with ferrohydrite. Kaolinite is the major clay mineral in the Quaternary bauxite and mainly coexists with gibbsites and anatase, which may have formed partially at the expense of gibbsite. Ferrohydrite and goethite are the major iron oxide in the Quaternary bauxite and they were formed during the Quaternary weathering.